Subgrading machine



INVENTOR EDWIN O. MARTINSON ATTORNEY K United States Patent O "i 3,396,642 SUBGRADING MACHINE E. 0. Martinson, Milwaukee, Wis., assigner to Koehring Company, Milwaukee, Wis., a corporation of Wisconsin Filed Mar. 16, 1967, Ser. No. 623,640 5 Claims. (Cl. 94-39) ABSTRACT 0F THE DISCLOSURE In a subgrading machine for road construction a cutting blade and a screed are actuated by a common vibrating mechanism which causes the cutting blade to reciprocate edgewise in a horizontal direction while the machine is advanced along a base course and which, at the same time, causes the screed to produce a gyratory tamping action upon the graded base material.

The invention relates to road making machinery, and it is concerned more particularly with the grading and compacting of a base course.

In order to facilitate the grading of a base course it has heretofore been suggested to mount an array of individual cutting blades in end to end relation at the underside of a vehicle frame, and to reciprocate such blades edgewise generally in the direction of vehicle travel while they are advanced in cutting position by propulsion of the machine. However, machines of this type as heretofore constructed are believed to have not been entirely satisfactory, particularly in the matter of manufacturing costs, because the necessary drive mechanisms for the individual blade sections were relatively elaborate and expensive.

The principal object of the present invention is to provide an improved subgrading machine which has an array of individual reciprocable grader blade sections, a like number of vibratory base compacting screed sections in trailing relation to the blade sections, and a simple and relatively inexpensive drive mechanism which will reciprocate the grader blade sections edgewise generally in the direction of vehicle travel while they are advanced in cutting position by propulsion of the machine, and which mechanism will at the same time vibrate the screed sections so as to compact the material of the base course which has been graded by the reciprocating blade sections.

A further object of the invention is to provide an improved subgrading machine in which a cutting blade section and an associated screed section are actuated by a common vibrating mechanism which simultaneously produces a gyratory tamping action of the screed section and an edgewise reciprocating movement of the blade section in a generally horizontal direction, and in which the vibratory stroke of the screed section may be controlled by a readily operable adjusting mechanism.

These and other objects and advantages are attained by the present invention, various novel features of which will be apparent from the description herein of a preferred embodiment of the invention shown by the accompanying drawings, and will be pointed out by the appended claims.

In the drawings:

FIG. l is an elevational side view of a base grading and compacting mechanism embodying the invention;

FIG. 2 is a top view, at a reduced scale, of the principal components of the mechanism shown in FIG. l, frame portions and other elements shown in FIG. l being broken away and omitted in FIG. 2;

FIG. 3 is a front elevation, at a reduced scale, of the mechanism shown in FIG. 1.

Referring to FIG. l, a conventionally constructed vehicle frame comprises front and rear transverse I-beams 1 and 2, a deck plate 3 and bracing connections between 3,396,642 Patented Aug. I3, 1968 the I-beams including pairs of laterally spaced bars 4 and 6 (FIG. 2). The frame is sustained in an elevated position above the ground level 7 by suitable running gear, not shown, which is power driven to propel the frame along a base course sidewise of the I-beams 1 and 2. As usual, the I-beams are of suilicient length to span a ground area of considerable width, and at its underside the frame carries an array of ground working tool units which are aligned longitudinally of the frame and are advanced in working position by propulsion of the vehicle frame on its running gear. All `of the tool units in the array are identical, and each is constructed according to the invention as follows.

As shown in FIGS. l and 2, a subframe 5 comprises a pair of generally triangular side members 8 and 9, a forward transverse connecting beam 10, and a transverse angle bar I1. The connecting beam 10 presents an upwardly and rearwardly inclined front flange, a rearwardly and downwardly inclined web, and a depending rear ange. The angle bar 11 is secured, as by welding, to the front edges of the side members 8 and 9 so that one of its flanges extends in a generally rearwardly and downwardly inclined direction and so that its other flange extends forwardly and downwardly at the forward end of the subframe.

The rear ends of the side members 8 and 9 are pivotally mounted at the underside of the rear I-beam 2, the side member 8 having a horizontal pivot connection 12 with the adjacent frame bar 4, and the side member 9 (FIG. 2) having a horizontal pivot connection 13 with the adjacent frame bar 6. A pair of suspension rods 14 and 16 (FIG. 3) connect the subframe with a pair of laterally spaced adjusting mechanisms 17 and 18, respectively, on top of the deck plate 3. The suspension rod 14 has a universal connection 19 at its lower end with the depending rear lflange of the beam 10, and the suspension rod 16 has a similar connection 21 (FIG. 3) with the beam 10. The adjusting mechanisms 17 and 18 are suitably constructed in conformity with established practice to raise and lower the suspension rods 14 and 16 for the purpose of profiling the base course as is well known in the art.

An angularly bent mold board section 22 extends in a generally upward direction in front of the subframe 5 and has a forwardly and downwardly inclined cutting edge strap 23 at its lower end. At its upper end the mold board section 22 is connected to the beam 10 of the subframe by a pair of generally upright leaf springs 24, 26 and by a pair of oblique leaf springs 27, 2S.

The upright leaf spring 24, as shown in FIG. l, extends between the front flange of the beam 10 to which it is secured by a bolted connection 29, and a rearwardly inclined top portion of the mold board 22 to which it is secured by a bolted connection 3i. As shown in FIGS. 2 and 3, the leaf spring 24 is located next to the side mem- -ber 8 of the subframe 5, and the leaf spring 26 is located next to the side member 9. The mounting of the leaf spring 26 corresponds to the mounting of the leaf spring 24 as shown in FIG. l.

The inclined leaf spring 27, as shown in FIG. l extends between the web of the beam 10 and a forwardly projecting top ange of the mold board section 22. Bolt connections 32 and 33 secure the leaf spring 27 in place. As shown in FIGS. 2 and 3, the leaf springs 27 and 2S are located in the lateral space between the upright leaf springs 24, 26. The mounting of the leaf spring 28 corresponds to the mounting of the leaf spring 27 shown in FIG. l. The leaf springs 24, 26 and 27, 28 thus cooperate to connect the base cutting assembly 22, 23 with the subframe 5 for edgewise back and forth swinging movement relative thereto in the direction of propulsion of the vehicle frame.

An apron 30 of flexible material is mounted at the underside Iof the I-beam 1 `and secured to the upper part of the mold board 22 at the right end of the latter as shown in FIG. 3, and a similar apron, not shown, may be mounted at the opposite end of the mold board for sealing purposes.

Forward thrust transmitting spring means which are aiorded by three laterally spaced coil springs 34, 36 and 37 (FIG. 3) are operatively interposed between the subframe and the mold board 22. As shown in FIG. l, the coil spring 34 is seated at one end on the rear of the mold board 22, and it bears at its other end upon the depending flange of the angle bar 11. The same explanations apply to the coil springs 36, 37. A backing coil spring 38 is alined with the coil spring 34, and corresponding backing coil springs, not shown, are alined with the coil springs 36 and 37.

Underlying the subframe 5 and spaced rearwardly from the mold board and cutting edge assembly 22, 23 is a vibrating mechanism generally designated by the reference numeral 39. As Shown in FIG. 2, the vibrating mechanism comprises `an elongated housing 41 which 'has alined shaft 'bearings 42 and 43 at its opposite ends. A generally cylindrical wall of the housing 41 encloses an elongated cylindrical rotor 44 which has co-axial eccentric journals 46 and 47 at its opposite ends. The journal 46 is rotatably supported in the bearing 43; and the journal 47 is rotatably supported in the bearing 42 and mounts a drive pulley 48 outside of the housing 41. The rotor 44 and journals 46, 47 provide, in effect, an eccentrically weighted shaft, and the housing 41 and bearings 42, 43 provide a support on which the eccentrically weighted shaft is journaled for rotation on a horizontal axis which extends transversely to the direction of vehicle propulsion.

Rigidly secured to the underside of the housing 41 is a rectangular screed section 50 which has a plane, upwardly angled front portion and an adjoining plane rear portion in parallel or approximately parallel relation to the surface of the base material which has been leveled by the preceding cutting edge strap 23.

The vibrator housing 41 is connected in back and forth thrust transmitting relation with the mold board 22 by a pair of laterally spaced links 49 and 51. The rear end of the link 49 has a horizontal pivot connection 52 with a pair of forwardly projecting ears 53 of the housing 41 next to the bearing 42, and the forward end of the link 49 has a horizontal pivot connection 54 with a pair of rearwardly projecting ears 56 of `the mold board 22. The link 51 is similarly mounted at its rear end on forwardly projecting ears 53 of the housing 41 next to the lbearing 43 by means of a horizontal pivot connection 52'; and the forward end of the link S1 has a horizontal pivot connection 54 with a pair of rearwardly projecting ears 56 of the mold board 22.

A belt drive for the vibrating mechanism 39 comprises V-belts 57 and 58. The belt 57 connects the sheave 48 with a double grooved sheave S9 which is mounted on the mold board 22 for rotation on the axis of the pivot connection 54. The belt 58 connects the sheave 59 with a driving sheave 61 on a shaft section 62 (FIG. 2) which is rotatably mounted on the subframe 5. The shaft section 62 has a suitable driving connection with a power source, not shown. A universally flexible coupling 63 on the shaft section 62 may connect it to the drive shaft section of the next tool unit in the array.

A resilient hold down mechanism for the vibrator housing 41 is mounted on the vehicle frame independently of the subframe 5. It comprises a U-frame 64, a double acting hydraulic ram 66, and a pair of coil springs 67 and 68. The legs 69 and 71 of the U-frame have horizontally alined pivot connections 72, 73, respectively, with angle iron hangers 74, 76 at the under side of the I-beam 2. A channel bar 77 at the closed end of the U-frame 64 is pivotally connected midway between its ends with the piston rod of the ram 66, and a pivot 78 connects the cylinder of the ram with the web of the I-beam 1. The coil spring 67 is seated on top of the vibrator housing 41 adjacent the bearing 42, and the upper end of the spring 67 bears against an angle iron brace 78 between the legs of the U-frame 64. The coil spring 68 is similarly interposed between tbe vibrator housing 41 and the brace 78 adjacent the bearing 43. Hanger straps 79 and 81 of iexible material, such as belting, provide a lifting connection between the U-frame 64 and the vibrator housing 41. The ram 66 is connected with a conventional hydraulic circuit, not shown; and may be operated to swing the U- frame 64 up or down about its pivot connection 72, 73 and to lock the U-frame in any selected position of pivotal adjustment relative to the vehicle frame.

In operation, the vehicle frame is adjusted on its running gear to an elevation above the ground which presents the cutting edge 23 in a desired working position. While the machine is advanced on its running gear, the eccentrically weighted shaft 44, 46, 47 is rotated at a relatively high speed by the V-belt drive 57, 58. Since the Vibrator housing 41 is in effect floatingly mounted on the vehicle frame by the provision of the leaf springs 24-28 and the links 49, 51, high speed rotation of the eccentrically journaled rotor 44 will produce a gyratory movement of the housing 41 and screed 50 relative to the vehicle frame.

As a result of such gyratory movement of the vibrator housing 41, the mold board 22 and its associated cutting edge 23 will be reciprocated edgewise in a generally horizontal direction while the cutting edge is advanced in working position by propulsion of 'the machine on its running gear. Experience has shown that rapid back and forth movement of the cutting edge greatly enhances its cutting eiciency. The gyratory movement of the vibrator housing 41 obviously also produces a tamping effect of the screed 50 upon the base material which has been leveled by the reciprocating mold board assembly.

The amplitude at which the vibrator housing 41 oscillates may be controlled by adjustment of the ram 66, expansion of the ram causing the ydownward pressure of the coil springs 67, 68 upon the housing to increase, and contraction of the ram causing the downward pressure to decrease. In this manner, the tamping effect of the screed may be readily regulated so as to avoid undesirable ripple of the compacted base course.

It should be understood that it is not intended to limit the invention to the hereindisclosed details of construction and that the invention includes such other forms of the machine as are embraced by the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. A subgrading machine comprising a vehicle frame; a gyratory vibrating mechanism floatingly mounted on said vehicle frame; a base compacting element connected with said vibrating mechanism for gyratory movement in unison therewith relative to said vehicle frame; and a base cutting element connected in thrust transmitting relation with said vibrating mechanism so as to be reciprocated edgewise in a generally horizontal direction relative to said vehicle frame by said gyratory movement of said vibrating mechanism.

2. A subgrading machine as set forth in claim 1 and further comprising downward thrust transmitting spring means operatively interposed between said vehicle frame and said vibrating mechanism.

3. A subgrading machine as set forth in claim 2 and further comprising a mounting structure for said spring means connected with said vehicle frame in up and down adjustable relation thereto.

4. A subgrading machine comprising, a vehicle fram'e; a subframe connected with said vehicle frame in up and down adjustable relation thereto; a base cutting element connected with said subframe for edgewise back and forth swinging movement relative thereto in the direction of propulsion of said vehicle frame; forward thrust transmitting spring means operatively interposed between said subframe and said cutting element; a vibrating mechanism comprising a support and an eccentrically Weighted shaft journaled on said support for rotation on a horizontal axis extending transversely to said direction of vehicle propulsion; a base compacting element secured to said support; and articulated connecting means between said support and cutting element operative to transmit thrust between said support and said cutting element in said direction of vehicle propulsion while accommodating base compacting vibratory movement of said support relative to said cutting element.

5. A subgrading machine as set forth in claim 4 and further comprising downward thrust transmitting spring means operatively interposed between said vehicle frame and said support.

References Cited UNITED STATES PATENTS NILE C. BYERS, I R., Primary Examiner. 

